U.S. patent application number 14/090007 was filed with the patent office on 2014-09-11 for polarization film and display device.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Hyeon Ho CHOI, Feifei FANG, Myung Sup JUNG, Myung Man KIM, Young Hwan KIM, Yong Joo LEE, Deuk Kyu MOON, Sang Ho PARK, Jong Hoon WON.
Application Number | 20140254012 14/090007 |
Document ID | / |
Family ID | 51487509 |
Filed Date | 2014-09-11 |
United States Patent
Application |
20140254012 |
Kind Code |
A1 |
MOON; Deuk Kyu ; et
al. |
September 11, 2014 |
POLARIZATION FILM AND DISPLAY DEVICE
Abstract
A polarization film, including: a hydrophobic polymer resin and
a dichroic dye represented by Chemical Formula 1: ##STR00001##
wherein in Chemical Formula 1, wherein, in Chemical Formula 1,
Ar.sup.1 is a substituted or unsubstituted C6 to C15 arylene group,
Ar.sup.2 is a C6 to C15 arylene group substituted with at least one
of a substituted or unsubstituted C1 to C20 alkyl group, a
substituted or unsubstituted C1 to C20 alkoxy group, a halogen atom
and a halogen-containing group, Ar.sup.3 is a C6 to C15 arylene
group substituted with an amide group, R.sup.1 is a substituted or
unsubstituted C1 to C20 alkyl group or a substituted or
unsubstituted C1 to C20 alkoxy group, R.sup.2 and R.sup.3 are each
independently a substituted or unsubstituted C1 to C20 alkyl group,
or R.sup.2 and R.sup.3 are linked to each other to form a ring, and
n is 1 or 2.
Inventors: |
MOON; Deuk Kyu; (Seoul,
KR) ; PARK; Sang Ho; (Anyang-si, KR) ; LEE;
Yong Joo; (Suwon-si, KR) ; WON; Jong Hoon;
(Yongin-si, KR) ; CHOI; Hyeon Ho; (Seoul, KR)
; KIM; Myung Man; (Suwon-si, KR) ; KIM; Young
Hwan; (Seongnam-si, KR) ; FANG; Feifei;
(Suwon-si, KR) ; JUNG; Myung Sup; (Seongnam-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
51487509 |
Appl. No.: |
14/090007 |
Filed: |
November 26, 2013 |
Current U.S.
Class: |
359/487.02 ;
252/585 |
Current CPC
Class: |
Y10T 428/1041 20150115;
G02B 1/08 20130101; C09K 2323/031 20200801; G02B 5/305
20130101 |
Class at
Publication: |
359/487.02 ;
252/585 |
International
Class: |
G02B 5/30 20060101
G02B005/30; G02B 1/08 20060101 G02B001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 11, 2013 |
KR |
10-2013-0025848 |
Claims
1. A polarization film, comprising: a hydrophobic polymer resin;
and a dichroic dye represented by Chemical Formula 1, ##STR00012##
wherein, in Chemical Formula 1, Ar.sup.1 is a substituted or
unsubstituted C6 to C15 arylene group, Ar.sup.2 is a C6 to C15
arylene group substituted with at least one of a substituted or
unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted
C1 to C20 alkoxy group, a halogen atom and a halogen-containing
group, Ar.sup.3 is a C6 to C15 arylene group substituted with an
amide group, R.sup.1 is a substituted or unsubstituted C1 to C20
alkyl group or a substituted or unsubstituted C1 to C20 alkoxy
group, R.sup.2 and R.sup.3 are each independently a substituted or
unsubstituted C1 to C20 alkyl group, or R.sup.2 and R.sup.3 are
linked to each other to form a ring, and n is 1 or 2.
2. The polarization film of claim 1, wherein the C6 to C15 arylene
group is a phenylene group, a naphthylene group, or a biphenylene
group.
3. The polarization film of claim 1, wherein Ar.sup.3 is a C6 to
C15 arylene group substituted with an acetamide group.
4. The polarization film of claim 1, wherein Ar.sup.3 is a C6 to
C15 arylene group substituted with an amide group and a substituted
or unsubstituted C1 to C20 alkoxy group.
5. The polarization film of claim 1, wherein the dichroic dye is
represented by Chemical Formula 2: ##STR00013## wherein, in
Chemical Formula 2, Ar.sup.1 is a substituted or unsubstituted C6
to C15 arylene group, R.sup.a is a substituted or unsubstituted C1
to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy
group, a halogen atom, or a halogen-containing group, R.sup.b is
hydrogen or a substituted or unsubstituted C1 to C20 alkoxy group,
R.sup.c is a substituted or unsubstituted C1 to C20 alkyl group,
R.sup.1 is a substituted or unsubstituted C1 to C20 alkyl group or
a substituted or unsubstituted C1 to C20 alkoxy group, R.sup.2 and
R.sup.3 are each independently a substituted or unsubstituted C1 to
C20 alkyl group, or R.sup.2 and R.sup.3 are linked to each other to
form a ring, and n is 1 or 2.
6. The polarization film of claim 1, wherein the dichroic dye is
represented by one of Chemical Formulae 3 to 6: ##STR00014##
7. The polarization film of claim 1, wherein the hydrophobic
polymer resin comprises a polyolefin, a polyamide, a polyacryl, a
polystyrene, a polyester, a polycarbonate, a polyimide, a copolymer
thereof, or a combination thereof.
8. The polarization film of claim 7, wherein the hydrophobic
polymer resin is a polyolefin, and the polyolefin is a combination
of polypropylene and a polyethylene-polypropylene copolymer.
9. The polarization film of claim 1, wherein the dichroic dye has a
solubility parameter of less than or equal to about 24.
10. The polarization film of claim 1, wherein a difference between
a solubility parameter of the hydrophobic polymer resin and a
solubility parameter of the dichroic dye is less than or equal to
about 8.0.
11. The polarization film of claim 1, wherein the dichroic dye is
included in an amount of about 0.01 to about 5 parts by weight,
based on 100 parts by weight of the hydrophobic polymer resin.
12. The polarization film of claim 11, wherein the dichroic dye is
included in an amount of about 0.05 to about 1 part by weight,
based on 100 parts by weight of the hydrophobic polymer resin.
13. The polarization film of claim 1, wherein the polarization film
has a dichroic ratio of about 3 to about 10 at maximum absorption
wavelength in a visible wavelength region, and the dichroic ratio
is represented by Equation 1:
DR=Log(1/T.sub..perp.)/Log(1/T.sub..parallel.) Equation 1 wherein,
in Equation 1, DR denotes a dichroic ratio of a polarization film,
T.sub..parallel. is a transmittance of light entering parallel to a
transmissive axis of the polarization film, and T.sub..perp. is a
transmittance of light entering perpendicular to the transmissive
axis of the polarization film.
14. The polarization film of claim 1, wherein the polarization film
has polarization efficiency of greater than or equal to about 90%,
and wherein polarization efficiency is obtained by Equation 2:
PE(%)=[(T.sub..parallel.-T.sub..perp.)/(T.sub..parallel.+T.sub..perp.)].s-
up.1/2.times.100 Equation 2 wherein, in Equation 2, PE denotes
polarization efficiency, T.sub..parallel. is a transmittance of
light entering parallel to a transmissive axis of the polarization
film, and T.sub..perp. is a transmittance of light entering
perpendicular to the transmissive axis of the polarization
film.
15. The polarization film of claim 1, wherein the polarization film
comprises a melt blend of the hydrophobic polymer resin and the
dichroic dye.
16. The polarization film of claim 15, wherein the dichroic dye is
dispersed in the hydrophobic polymer resin, and the hydrophobic
polymer resin is elongated in a uniaxial direction by about 400
percent to about 1,000 percent.
17. An antireflective film comprising the polarization film
according to claim 1, and a compensation film.
18. A display device comprising the polarization film according to
claim 1.
19. The display device of claim 18, wherein the display device is a
liquid crystal display or an organic light emitting diode device.
Description
[0001] This application claims priority to and the benefit of
Korean Patent Application No. 10-2013-0025848, filed on Mar. 11,
2013, and all the benefits accruing therefrom under 35 U.S.C.
.sctn.119, the content of which is incorporated herein in its
entirety by reference.
BACKGROUND
[0002] 1. Field
[0003] A polarization film and a display device including the
polarization film are disclosed.
[0004] 2. Description of the Related Art
[0005] A display device such as a liquid crystal display ("LCD")
and an organic light emitting diode ("OLED") device includes a
polarization plate attached to the outside of a display panel. The
polarization plate transmits light of a specific wavelength and
absorbs or reflects light of other wavelengths. Thus, the
polarization plate may control the direction of incident light on
the display panel or light emitted from the display panel.
[0006] The polarization plate generally includes a polarizer and a
protective layer for the polarizer. The polarizer may be formed,
for example, from polyvinyl alcohol ("PVA"), and the protective
layer may be formed, for example, from triacetyl cellulose
("TAC").
[0007] However, manufacture of the polarization plate including the
polarizer and the protective layer is complicated and expensive,
and also results in a thick polarization plate which leads to an
increased thickness of a display device.
[0008] Accordingly, there remains a need in the art for a
polarization film that does not require a protective layer.
SUMMARY
[0009] An embodiment provides a polarization film that may have
improved polarization properties.
[0010] Another embodiment provides a display device including the
polarization film.
[0011] A polarization film according to an embodiment includes a
hydrophobic polymer resin and a dichroic dye represented by
Chemical Formula 1,
##STR00002##
[0012] Wherein, in Chemical Formula 1,
[0013] Ar.sup.1 is a substituted or unsubstituted C6 to C15 arylene
group,
[0014] Ar.sup.2 is a C6 to C15 arylene group substituted with at
least one of a substituted or unsubstituted C1 to C20 alkyl group,
a substituted or unsubstituted C1 to C20 alkoxy group, a halogen
atom and a halogen-containing group,
[0015] Ar.sup.3 is a C6 to C15 arylene group substituted with an
amide group,
[0016] R.sup.1 is a substituted or unsubstituted C1 to C20 alkyl
group or a substituted or unsubstituted C1 to C20 alkoxy group,
[0017] R.sup.2 and R.sup.3 are each independently a substituted or
unsubstituted C1 to C20 alkyl group, or R.sup.2 and R.sup.3 are
linked to each other to form a ring, and
[0018] n is 1 or 2.
[0019] The C6 to C15 arylene group may be a phenylene group, a
naphthylene group, or a biphenylene group.
[0020] In Chemical Formula 1, Ar.sup.3 may be a C6 to C15 arylene
group substituted with an acetamide group.
[0021] In Chemical Formula 1, Ar.sup.3 may be a C6 to C15 arylene
group substituted with an amide group and a substituted or
unsubstituted C1 to C20 alkoxy group.
[0022] The dichroic dye may be represented by Chemical Formula
2.
##STR00003##
[0023] In Chemical Formula 2,
[0024] Ar.sup.1 is a substituted or unsubstituted C6 to C15 arylene
group,
[0025] R.sup.a is a substituted or unsubstituted C1 to C20 alkyl
group, a substituted or unsubstituted C1 to C20 alkoxy group, a
halogen atom, or a halogen-containing group,
[0026] R.sup.b is hydrogen or a substituted or unsubstituted C1 to
C20 alkoxy group,
[0027] R.sup.c is a substituted or unsubstituted C1 to C20 alkyl
group,
[0028] R.sup.1 is a substituted or unsubstituted C1 to C20 alkyl
group or a substituted or unsubstituted C1 to C20 alkoxy group,
[0029] R.sup.2 and R.sup.3 are each independently a substituted or
unsubstituted C1 to C20 alkyl group, or R.sup.2 and R.sup.3 are
linked to each other to form a ring, and
[0030] n is 1 or 2.
[0031] The dichroic dye may be represented by one of Chemical
Formulae 3 to 6.
##STR00004##
[0032] The hydrophobic polymer resin may include a polyolefin, a
polyamide, a polyacryl, a polystyrene, a polyester, a
polycarbonate, a polyimide, a copolymer thereof, or a combination
thereof.
[0033] The hydrophobic polymer resin may be a polyolefin, and the
polyolefin may be a combination of polypropylene and a
polyethylene-polypropylene copolymer.
[0034] The dichroic dye may have a solubility parameter of less
than or equal to about 24.
[0035] A difference between a solubility parameter of the
hydrophobic polymer resin and a solubility parameter of the
dichroic dye may be less than or equal to about 8.0.
[0036] The dichroic dye may be present in an amount of about 0.01
to about 5 parts by weight based on a total of 100 parts by weight
of the hydrophobic polymer resin.
[0037] The dichroic dye may be present in an amount of about 0.05
to about 1 parts by weight based on a total of 100 parts by weight
of the hydrophobic polymer resin.
[0038] The polarization film may have a dichroic ratio of about 3
to about 10 at maximum absorption wavelength in a visible ray
region, wherein the dichroic ratio is represented by Equation
1.
DR=Log(1/T.sub..perp.)/Log(1/T.sub..parallel.) Equation 1
[0039] In Equation 1,
[0040] DR denotes a dichroic ratio of a polarization film,
[0041] T.sub..parallel. is transmittance of light entering parallel
to the transmissive axis of a polarization film, and
[0042] T.sub..perp. is transmittance of light entering
perpendicular to the transmissive axis of the polarization
film.
[0043] The polarization film may have polarization efficiency of
greater than or equal to about 90%, wherein polarization efficiency
is obtained by Equation 2.
PE(%)=[(T.sub..parallel.-T.sub..perp.)/(T.sub..parallel.+T.sub..perp.)].-
sup.1/2.times.100 Equation 2
[0044] In Equation 2,
[0045] PE denotes polarization efficiency,
[0046] T.sub..parallel. is transmittance of light entering parallel
to the transmissive axis of a polarization film, and
[0047] T.sub..perp. is transmittance of light entering
perpendicular to the transmissive axis of the polarization
film.
[0048] The polarization film may be a melt blend of the hydrophobic
polymer resin and the dichroic dye.
[0049] The dichroic dye may be distributed in the hydrophobic
polymer resin, and the hydrophobic polymer resin may be elongated
in a uniaxial direction by about 400 to about 1,000%.
[0050] According to another embodiment, an antireflective film
including the polarization film and a compensation film is
provided.
[0051] According to yet another embodiment, a display device
including the polarization film is provided.
[0052] The display device may be a liquid crystal display or an
organic light emitting diode device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] These and other embodiments will become apparent and more
readily appreciated from the following description taken in
conjunction with the accompanying drawings in which:
[0054] FIG. 1 is schematic view of a polarization film according to
an embodiment;
[0055] FIG. 2 is a cross-sectional view showing a liquid crystal
display ("LCD") according to an embodiment;
[0056] FIG. 3 is a cross-sectional view an organic light emitting
diode ("OLED") device according to an embodiment; and
[0057] FIG. 4 is a graph of dichroic ratio (DR) versus wavelength
(nanometer) showing dichroic ratios in a visible ray region
according to the polarization films according to Examples 1 to
4.
DETAILED DESCRIPTION
[0058] This disclosure will be described more fully hereinafter
with reference to the accompanying drawings, in which exemplary
embodiments of the present disclosure are shown. This disclosure
may, however, be embodied in many different forms and should not be
construed as limited to the exemplary embodiments set forth herein;
rather, these embodiments are provided so that this disclosure will
fully convey the scope of the invention to those skilled in the
art. Thus, in some exemplary embodiments, well known technologies
are not specifically explained to avoid ambiguous understanding of
the present invention. Unless otherwise defined, all terms used in
the specification (including technical and scientific terms) may be
used with meanings commonly understood by a person having ordinary
knowledge in the art. Further, unless explicitly defined to the
contrary, the terms defined in a generally-used dictionary are not
ideally or excessively interpreted. In addition, unless explicitly
described to the contrary, the word "comprise" and variations such
as "comprises" or "comprising" will be understood to imply the
inclusion of stated elements but not the exclusion of any other
elements.
[0059] Unless specifically described to the contrary, a singular
form includes a plural form.
[0060] The exemplary embodiments of the present invention described
in the specification are explained referring to ideal exemplary
drawings of schematic diagrams. Therefore, the parts exemplified in
the drawings have outline properties and they are not to limit the
categories of the invention. The same reference numerals designate
the same constituent elements throughout the specification.
[0061] As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items.
Expressions such as "at least one of," when preceding a list of
elements, modify the entire list of elements and do not modify the
individual elements of the list.
[0062] It will be understood that, although the terms first,
second, third etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another element,
component, region, layer, or section. Thus, a first element,
component, region, layer, or section discussed below could be
termed a second element, component, region, layer, or section
without departing from the teachings of the present
embodiments.
[0063] Exemplary embodiments are described herein with reference to
cross section illustrations that are schematic illustrations of
idealized embodiments. As such, variations from the shapes of the
illustrations as a result, for example, of manufacturing techniques
and/or tolerances, are to be expected. Thus, embodiments described
herein should not be construed as limited to the particular shapes
of regions as illustrated herein but are to include deviations in
shapes that result, for example, from manufacturing. For example, a
region illustrated or described as flat may, typically, have rough
and/or nonlinear features. Moreover, sharp angles that are
illustrated may be rounded. Thus, the regions illustrated in the
figures are schematic in nature and their shapes are not intended
to illustrate the precise shape of a region and are not intended to
limit the scope of the present claims.
[0064] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting. As
used herein, the singular forms "a," "an" and "the" are intended to
include the plural forms as well, unless the context clearly
indicates otherwise. Unless specified otherwise, the term "or"
means "and/or".
[0065] As used herein, a "mixture" refers to a combination of
components in any form, for example solution, alloy, or
solid/liquid.
[0066] As used herein, when a definition is not otherwise provided,
the term `substituted` refers to a compound or group substituted
with at least one substituent selected from a halogen (F, Br, Cl,
or I), a C1 to C20 alkoxy group, a C1 to C20 alkylthio group, a
cyano group (--CN), an amino group (--NRR', wherein R and R' are
independently hydrogen or a C1 to C6 alkyl group), a C1 to C20
ester group, a C1 to C20 alkyl group, a C1 to C20 aryl group, a C2
to C20 alkenyl group, a C2 to C20 alkynyl group, a hydroxy group
(--OH), a nitro group (--NO.sub.2), an azido group (--N.sub.3), an
amidino group (--C(.dbd.NH)NH.sub.2), a hydrazine group
(--NHNH.sub.2), a hydrazono group (.dbd.N(NH.sub.2), an aldehyde
group (--C(.dbd.O)H), a carbamoyl group (--C(.dbd.O)NH.sub.2), a
thiol group (--SH), an ester group (--C(.dbd.O)OR, wherein R is a
C1 to C6 alkyl group or a C6 to C12 aryl group), a carboxyl group
(--C(.dbd.O)OH) or a salt thereof (--C(.dbd.O)OM, wherein M is an
organic or inorganic cation), a sulfonic acid group (--SO.sub.3H)
or a salt thereof (--SO.sub.3M, wherein M is an organic or
inorganic cation), a phosphoric acid group (--PO.sub.3H.sub.2) or a
salt thereof (--PO.sub.3MH or --PO.sub.3M.sub.2, wherein M is an
organic or inorganic cation), and a combination thereof, in place
of at least one hydrogen of the compound.
[0067] As used herein, the term "alkyl" refers to a monovalent
group derived from a straight or branched chain saturated aliphatic
hydrocarbon, and having a specified number of carbon atoms. Alkyl
groups include, for example, methyl, ethyl, propyl, isopropyl, and
hexyl.
[0068] As used herein, the term "alkenyl" refers to a monovalent
group derived from a straight or branched chain saturated aliphatic
hydrocarbon, having at least one double bond, and having a
specified number of carbon atoms. Alkenyl groups include, for
example, ethenyl and propenyl.
[0069] As used herein, the term "alkynyl" refers to a monovalent
group derived from a straight or branched chain saturated aliphatic
hydrocarbon, having at least one triple bond, and having a
specified number of carbon atoms. Alkynyl groups include, for
example, ethynyl and propynyl.
[0070] As used herein, the term "alkoxy" indicates "alkyl-O--",
wherein the alkyl is the same as described above and having the
specified number of carbon atoms. Non-limiting examples of the
alkoxy group include methoxy, ethoxy, 1-propoxy, 2-propoxy,
n-butoxy, t-butoxy, pentyloxy, hexyloxy, cyclopropoxy, and
cyclohexyloxy.
[0071] As used herein, the term "alkylthio" indicates "alkyl-S--",
wherein the alkyl is the same as described above and having the
specified number of carbon atoms. Non-limiting examples of the
alkylthio group include methylthio, ethylthio, 1-propylthio,
2-propylthio, n-butylthio, t-butylthio, pentylthio, hexylthio,
cyclopropylthio, and cyclohexylthio.
[0072] As used herein, the term "aryl" group, which is used alone
or in combination, indicates a monovalent group derived from an
aromatic hydrocarbon containing at least one ring, and having the
specified number of carbon atoms. As used herein, the term "aryl"
is construed as including a group with an aromatic ring fused to at
least one cycloalkyl ring. Non-limiting examples of the "aryl"
group include phenyl, naphthyl, and tetrahydronaphthyl.
[0073] As used herein, the term "arylene" indicates a divalent
group formed by the removal of two hydrogen atoms from one or more
rings of an aromatic hydrocarbon, wherein the hydrogen atoms may be
removed from the same or different rings, each of which rings may
be aromatic or nonaromatic. Non-limiting examples of the "arylene"
group include a phenylene group, a naphthylene group, or a
biphenylene group.
[0074] Hereinafter, a polarization film according to an embodiment
is described.
[0075] FIG. 1 is schematic view of a polarization film according to
an embodiment.
[0076] Referring to FIG. 1, a polarization film 70 according to an
embodiment includes a polymer resin 71 and a dichroic dye 72.
[0077] The polymer resin 71 may be a hydrophobic polymer resin, for
example, a polyolefin such as polyethylene ("PE"), polypropylene
("PP"), and a copolymer thereof; a polyamide such as nylon and an
aromatic polyamide; a polyester such as polyethylene terephthalate
("PET"), polyethylene terephthalate glycol ("PETG"), and
polyethylene naphthalate; a polyacrylic such as
polymethyl(meth)acrylate; a polystyrene such as polystyrene ("PS")
and an acrylonitrile-styrene copolymer; a polycarbonate; a vinyl
chloride-based resin; a polyimide; a sulfone resin; a
polyethersulfone; a polyether-etherketone; a polyphenylene sulfide;
a vinyl alcohol resin; a vinylidene chloride resin; a vinylbutyral
resin; an allylate resin; a polyoxymethylene; an epoxy resin; a
copolymer thereof; or a combination thereof.
[0078] In an embodiment, the polymer resin 71 may be, for example,
polyethylene ("PE"), polypropylene ("PP"), polyethylene
terephthalate ("PET"), polyethylene terephthalate glycol ("PETG"),
nylon, a copolymer thereof, or a combination thereof.
[0079] The polymer resin 71 may be, for example, a mixture of at
least two polymers selected from polyethylene ("PE"), polypropylene
("PP"), and a polyethylene-polypropylene ("PE-PP") copolymer, and
in an embodiment, a combination of polypropylene ("PP") and a
polyethylene-polypropylene ("PE-PP") copolymer.
[0080] The polypropylene ("PP") may have, for example, a melt flow
index ("MFI") of about 0.1 gram (g)/10 minute (min) to about 5 g/10
min. Herein, the melt flow index ("MFI") shows the amount of a
polymer in a melt state flowing per 10 minutes, and relates to
viscosity of the polymer in a melt state. In other words, as the
melt flow index ("MFI") is lower, the polymer has higher viscosity,
while as the melt flow index ("MFI") is higher, the polymer has
lower viscosity. When the polypropylene has a melt flow index
("MFI") within the foregoing range, properties of a final product
as well as workability may be effectively improved. In an
embodiment, the polypropylene may have a melt flow index ("MFI")
ranging from about 0.5 g/10 min to about 5 g/10 min.
[0081] The polyethylene-polypropylene ("PE-PP") copolymer may
include about 1 percent by weight ("weight %") to about 50 weight %
of an ethylene group based on the total amount of the copolymer.
When the polyethylene-polypropylene ("PE-PP") copolymer includes
the ethylene group within the foregoing range, phase separation of
the polypropylene and the polyethylene-polypropylene ("PE-PP")
copolymer may be effectively prevented or suppressed. In addition,
the polyethylene-polypropylene ("PE-PP") copolymer may improve an
elongation ratio during elongation as well as have excellent light
transmittance and alignment, improving polarization
characteristics. In an embodiment, the polyethylene-polypropylene
("PE-PP") copolymer may include an ethylene group in an amount of
about 1 weight % to about 25 weight % based on the total amount of
the copolymer.
[0082] The polyethylene-polypropylene ("PE-PP") copolymer may have
a melt flow index ("MFI") ranging from about 5 g/10 min to about 15
g/10 min. When the polyethylene-polypropylene ("PE-PP") copolymer
has a melt flow index ("MFI") within the foregoing range,
properties of a final product as well as workability may be
effectively improved. In an embodiment, the
polyethylene-polypropylene ("PE-PP") copolymer may have a melt flow
index ("MFI") ranging from about 10 g/10 min to about 15 g/10
min.
[0083] The polymer resin 71 may include the polypropylene ("PP")
and the polyethylene-polypropylene copolymer ("PE-PP") in a weight
ratio of about 1:9 to about 9:1. When the polypropylene ("PP") and
the polyethylene-polypropylene ("PE-PP") copolymer are included
within the ratio range, the polypropylene may be prevented from
crystallizing and may have excellent mechanical strength, thus
effectively improving the haze characteristic. In an embodiment,
the polymer resin 71 may include the polypropylene ("PP") and the
polyethylene-polypropylene ("PE-PP") copolymer in a weight ratio of
about 4:6 to about 6:4, and in another embodiment, in a weight
ratio of about 5:5.
[0084] The polymer resin 71 may have a melt flow index ("MFI")
ranging from about 1 g/10 min to about 15 g/10 min. When the
polymer resin 71 has a melt flow index ("MFI") within the foregoing
range, the polymer resin 71 may not only secure excellent light
transmittance since crystals are not excessively formed in the
resin, but may also have appropriate viscosity for manufacturing a
film and thus have improved workability. In an embodiment, the
polymer resin 71 may have a melt flow index ("MFI") ranging from
about 5 g/10 min to about 15 g/10 min.
[0085] The polymer resin 71 may have haze ranging from less than or
equal to about 5%. When the polymer resin 71 has haze within the
foregoing range, transmittance may be increased, and thus excellent
optical properties may be secured. In an embodiment, the polymer
resin 71 may have haze of less than or equal to about 2%, and in
another embodiment, about 0.5% to about 2%.
[0086] The polymer resin 71 may have crystallinity of less than or
equal to about 50%. When the polymer resin 71 has crystallinity
within the foregoing range, the polymer resin 71 may have lower
haze and accomplish excellent optical properties. In an embodiment,
the polymer resin 71 may have crystallinity of about 30% to about
50%.
[0087] The polymer resin 71 may have light transmittance of greater
than or equal to about 85% in a wavelength region of about 380 nm
to about 780 nm. The polymer resin 71 may be elongated in a
uniaxial direction. The direction may be the longitudinal direction
of the dichroic dye 72.
[0088] The dichroic dye 72 may be distributed (for example,
dispersed) into the polymer resin 71 and aligned in the elongation
direction of the polymer resin 71. The dichroic dye 72 may be a
material that transmits one perpendicular polarization component
out of two perpendicular polarization components in a predetermined
wavelength region.
[0089] The dichroic dye 72 may be represented by the following
Chemical Formula 1.
##STR00005##
[0090] In Chemical Formula 1,
[0091] Ar.sup.1 is a substituted or unsubstituted C6 to C15 arylene
group,
Ar.sup.2 is a C6 to C15 arylene group substituted with at least one
of a substituted or unsubstituted C1 to C20 alkyl group, a
substituted or unsubstituted C1 to C20 alkoxy group, a halogen atom
and a halogen-containing group,
[0092] Ar.sup.3 is a C6 to C15 arylene group substituted with an
amide group,
[0093] R.sup.1 is a substituted or unsubstituted C1 to C20 alkyl
group or a substituted or unsubstituted C1 to C20 alkoxy group,
[0094] R.sup.2 and R.sup.3 are each independently a substituted or
unsubstituted C1 to C20 alkyl group, or R.sup.2 and R.sup.3 are
linked to each other to form a ring, and
[0095] n is 1 or 2.
[0096] The C6 to C15 arylene group may be a phenylene group, a
naphthylene group, or a biphenylene group.
[0097] In Chemical Formula 1, Ar.sup.3 may be a C6 to C15 arylene
group substituted with an acetamide group. Ar.sup.3 may be a
di-substituted C6 to C15 arylene group, for example a C6 to C15
arylene group substituted with an amide group and a substituted or
unsubstituted C1 to C20 alkoxy group.
[0098] The dichroic dye 72 may be represented by the following
Chemical Formula 2.
##STR00006##
[0099] In Chemical Formula 2,
[0100] Ar.sup.1 is a substituted or unsubstituted C6 to C15 arylene
group,
[0101] R.sup.a is a substituted or unsubstituted C1 to C20 alkyl
group, a substituted or unsubstituted C1 to C20 alkoxy group, a
halogen atom, or a halogen-containing group,
[0102] R.sup.b is hydrogen or a substituted or unsubstituted C1 to
C20 alkoxy group,
[0103] R.sup.c is a substituted or unsubstituted C1 to C20 alkyl
group,
[0104] R.sup.1 is a substituted or unsubstituted C1 to C20 alkyl
group or a substituted or unsubstituted C1 to C20 alkoxy group,
[0105] R.sup.2 and R.sup.3 are each independently a substituted or
unsubstituted C1 to C20 alkyl group, or R.sup.2 and R.sup.3 are
linked to each other to form a ring, and
[0106] n is 1 or 2.
[0107] The C6 to C15 arylene group may be a phenylene group, a
naphthylene group, or a biphenylene group.
[0108] In Chemical Formula 2, R.sup.c may be a methyl group.
[0109] The dichroic dye 72 may be, for example represented by one
of the following Chemical Formulae 3 to 6.
##STR00007##
[0110] The dichroic dye 72 may be used singularly or in a mixture
of two or more.
[0111] The dichroic dye 72 may be included in an amount of about
0.01 to about 5 parts by weight based on a total of 100 parts by
weight of the polymer resin 71. When the dichroic dye 72 is
included within the foregoing range, sufficient polarization
properties may be obtained without deteriorating transmittance of a
polarization film. The dichroic dye 72 may be included in an amount
of about 0.05 to about 1 part by weight within the range based on a
total of 100 parts by weight of the polymer resin 71.
[0112] The polarization film 70 may be a melt blend of the polymer
resin 71 and the dichroic dye 72. The melt blend may be obtained by
melt-blending a composition for a polarization film including the
polymer resin 71 and the dichroic dye 72 at a temperature of
greater than or equal to a melting point ("T.sub.m") of the polymer
resin 71. The composition for a polarization film may include the
above-described polymer resin 71 and dichroic dye 72. The polymer
resin 71 and the dichroic dye 72 are respectively a solid type such
as a powder. The composition for a polarization film may include,
for example, a solid content of greater than or equal to about 90
weight % but not a solvent.
[0113] A difference between a solubility parameter of the
hydrophobic polymer resin 71 and a solubility parameter of the
dichroic dye 72 may be less than or equal to about 8.0. The
solubility parameter illustrates an interaction degree to which two
or more compounds interact. The smaller solubility parameter
difference the compounds have, the larger degree of interaction
they have, while the larger solubility parameter difference the
compounds have, the smaller degree of interaction they have. Within
the foregoing range, a difference between a solubility parameter of
the hydrophobic polymer resin 71 and a solubility parameter of the
dichroic dye 72 may be less than or equal to about 7.4.
[0114] The solubility parameter has a relation with the structure
of a compound. When the dichroic dye 72 and the polymer resin 71
have a solubility parameter difference within the foregoing range,
the polymer resin 71 and the dichroic dye 72 have high degree of
interaction during the manufacture of a polarization film, and may
increase the melt-blending property and thus prevent agglomeration
of the dichroic dyes 72 and uniformly disperse the dichroic dye 72
in the polymer resin 71.
[0115] When the polymer resin 71 is a polyolefin, a solubility
parameter of the polyolefin may be about 15 to about 18. When the
dichroic dye 72 is used with the polyolefin, a solubility parameter
of the dichroic dye 72 may be less than or equal to about 24, for
example about 15 to about 24.
[0116] The polarization film 70 may be manufactured by
melt-blending and elongating the composition for a polarization
film.
[0117] In an embodiment, the polarization film 70 may be
manufactured by, for example, melt-blending a composition for a
polarization film including the polymer resin and the dichroic dye,
putting the composition in the melt blend and pressing it into a
sheet, and elongating the sheet in a uniaxial direction.
[0118] The melt-blending may be performed at a temperature of less
than or equal to about 300.degree. C., and in an embodiment,
ranging from about 50 to about 300.degree. C.
[0119] The sheet may be formed by putting the melt blend in the
mold, and pressing it with a high pressure or discharging it in a
chill roll through a T-die.
[0120] The elongation in a uniaxial direction may be performed at a
temperature ranging from about 30 to about 200.degree. C. at an
elongation rate ranging from about 400% to about 1,000%. The
elongation rate refers to a length ratio of after the elongation to
before the elongation of the sheet, and means the elongated extent
of the sheet after uniaxial elongation.
[0121] The polarization film 70 may have a dichroic ratio of about
3 to about 10 at a maximum absorption wavelength
(".lamda..sub.max") in a visible ray region. Herein, the dichroic
ratio may be calculated by dividing plane polarization absorbance
in a vertical direction with the axis of a polymer by polarization
absorbance in a horizontal direction according to the following
Equation 1.
DR=Log(1/T.sub..perp.)/Log(1/T.sub..parallel.) Equation 1
[0122] In Equation 1,
[0123] DR denotes a dichroic ratio of a polarization film,
[0124] T.sub..parallel. is light transmittance of light entering
parallel to the transmissive axis of a polarization film, and
[0125] T.sub..perp. is light transmittance of light entering
perpendicular to the transmissive axis of the polarization
film.
[0126] The dichroic ratio shows to what degree the dichroic dyes 72
are arranged in the polarization film 70 in one direction. When the
polarization film 70 has a dichroic ratio within the foregoing
range in the wavelength region, the dichroic dyes 72 are arranged
according to arrangement of the polymer chains, improving
polarization properties of the polarization film 70.
[0127] The polarization film 70 may have polarization efficiency of
greater than or equal to about 90%, and in an embodiment, ranging
from about 95% to about 100% within the range. Herein, the
polarization efficiency may be obtained by the following Equation
2.
PE(%)=[(T.sub..parallel.-T.sub..perp./(T.sub..parallel.+T.sub..perp.)].s-
up.1/2.times.100 Equation 2
[0128] In Equation 2,
[0129] PE denotes polarization efficiency,
[0130] T.sub..parallel. is transmittance of light entering parallel
to the transmissive axis of a polarization film, and
[0131] T.sub..perp. is transmittance of light entering
perpendicular to the transmissive axis of the polarization
film.
[0132] The polarization film 70 may have light transmittance of
greater than or equal to about 30%, and in an embodiment, ranging
from about 30% to about 95% within the range. When the polarization
film 70 having light transmittance within the foregoing ranges is
applied to one side of a display device, light emitting from the
display device may not be prevented.
[0133] The polarization film 70 may have a relatively low thickness
of less than or equal to about 100 micrometers (".mu.m"), and for
example, ranging from about 30 .mu.m to about 95 .mu.m. The
polarization film 70 has a thickness within the foregoing ranges,
and thus may be thinner than a polarization plate requiring a
protective layer such as triacetyl cellulose ("TAC") and contribute
to realizing a thin display device.
[0134] The polarization film may be applied to various display
devices.
[0135] The display device may be a liquid crystal display
("LCD").
[0136] FIG. 2 is a cross-sectional view showing a liquid crystal
display ("LCD") according to an embodiment.
[0137] Referring to FIG. 2, the liquid crystal display ("LCD")
includes a liquid crystal panel 10 and a polarization film 20
disposed on both the lower part and the upper part of the liquid
crystal display panel 10.
[0138] The liquid crystal panel 10 may be a twist nematic ("TN")
mode panel, a patterned vertical alignment ("PVA") mode panel, an
in-plane switching ("IPS") mode panel, an optically compensated
bend ("OCB") mode panel, and the like.
[0139] The liquid crystal display panel 10 includes a first display
panel 100, a second display panel 200, and a liquid crystal layer
300 interposed between the first display panel 100 and the second
display panel 200.
[0140] The first display panel 100 may include, for example, a thin
film transistor (not shown) formed on a substrate (not shown) and a
first electric field generating electrode (not shown) connected
thereto. The second display panel 200 may include, for example, a
color filter (not shown) formed on a substrate and a second
electric field generating electrode (not shown). However, it is not
limited thereto, and the color filter may be included in the first
display panel 100, and both the first electric field generating
electrode and the second electric field generating electrode may be
disposed in the first display panel 100.
[0141] The liquid crystal layer 300 may include a plurality of
liquid crystal molecules. The liquid crystal molecules may have
positive or negative dielectric anisotropy. When the liquid crystal
molecules have positive dielectric anisotropy, the long axis
thereof may be aligned substantially parallel to the surface of the
first display panel 100 and the second display panel 200 when not
applying an electric field, and may be aligned substantially
perpendicular to the surface of the first display panel 100 and the
second display panel 200 when applying an electric field. On the
contrary, when the liquid crystal molecules have negative
anisotropy, the long axis thereof may be aligned substantially
perpendicular to the surface of the first display panel 100 and the
second display panel 200 when not applying an electric field, and
may be aligned substantially parallel to the surface of the first
display panel 100 and the second display panel 200 when applying an
electric field.
[0142] The polarization film 20 is disposed on the outside of the
liquid crystal display panel 10. Although it is shown to be
disposed on the upper part and lower part of the liquid crystal
display panel 10 in the drawing, it may be formed on either the
upper part or the lower part of liquid crystal display panel
10.
[0143] The polarization film 20 includes a polymer resin and a
dichroic dye, which are the same as described above.
[0144] The display device may be an organic light emitting diode
("OLED") device.
[0145] FIG. 3 is a cross-sectional view an organic light emitting
diode ("OLED") device according to an embodiment.
[0146] Referring to FIG. 3, an organic light emitting diode
("OLED") device according to an embodiment includes a base
substrate 410, a lower electrode 420, an organic emission layer
430, an upper electrode 440, an encapsulation substrate 450, a
compensation film 460, and a polarization film 470.
[0147] The base substrate 410 may be formed of glass or
plastic.
[0148] Either of the lower electrode 420 and the upper electrode
440 may be an anode, while the other is a cathode. The anode is an
electrode where holes are injected, and is formed of a transparent
conductive material having a high work function and externally
transmitting entered light, for example, ITO or IZO. The cathode is
an electrode where electrons are injected, is formed of a
conducting material having a low work function and having no
influence on an organic material, and is selected from, for
example, aluminum (Al), calcium (Ca), and barium (Ba).
[0149] The organic emission layer 430 includes an organic material
emitting light when a voltage is applied between the lower
electrode 420 and the upper electrode 440.
[0150] An auxiliary layer (not shown) may be included between the
lower electrode 420 and the organic emission layer 430 and between
the upper electrode 440 and the organic emission layer 430. The
auxiliary layer may include at least one of a hole transport layer
("HTL"), a hole injection layer ("HIL"), an electron injection
layer ("EIL"), and an electron transport layer ("ETL") for
balancing electrons and holes.
[0151] The encapsulation substrate 450 may be made of glass, metal,
or a polymer. The lower electrode 420, the organic emission layer
430, and the upper electrode 440 are sealed to prevent moisture
and/or oxygen from externally flowing in.
[0152] The compensation film 460 may circularly polarize light
passing through the polarization film 470 and generate a phase
difference, and thus have an influence on reflection and absorption
of the light. In an embodiment, the compensation film 460 may be,
for example, a phase difference film such as .lamda./4 plate, and
may be omitted depending on the case.
[0153] The polarization film 470 may be disposed at a display
screen. For example, the polarization film 470 may be disposed
outside of the base substrate 410 in a bottom emission type in
which light emits from the base substrate 410, and outside of the
encapsulation substrate 450 in a top emission type in which light
emits from the encapsulation substrate 450.
[0154] The polarization film 470 includes a polymer resin and a
dichroic dye. The polarization film 470 may play a role of a light
absorption layer absorbing external light and thus prevent display
characteristic deterioration due to reflection of the external
light.
[0155] The compensation film 460 and polarization film 470 may be
disposed at a display screen of an organic light emitting diode
("OLED") device and thus may play a role of an antireflective film
preventing reflection of light flowing in from the outside. The
antireflective film may prevent visibility deterioration due to the
light flowing in from the outside.
[0156] Hereinafter, the embodiments are illustrated in more detail
with reference to examples. However, they are exemplary
embodiments, and the present invention is not limited thereto.
Synthesis of Dichroic Dye
Synthesis Example 1
1-1. Synthesis of Monoazo Compound
[0157] 10 g (41.1 mmol) of 4-(4-nitrophenylazo)phenol (TCI, Japan)
is dissolved in 200 mL of acetone, and 8.5 mL (48.9 mmol) of
1-bromooctane and 11.4 g (82.5 mmol) of potassium carbonate
(K.sub.2CO.sub.3) are added thereto. The reaction mixture is
refluxed and agitated at 60.degree. C. for 24 hours and then cooled
down to room temperature. The agitated mixture is concentrated and
purified through silica gel column chromatography
(CH.sub.2Cl.sub.2:n-hexane=2:1), to give 12.3 g (34.6 mmol) of a
4-nitro compound. A yield of the compound is 84%.
[0158] 5.7 g (16.0 mmol) of the 4-nitrocompound is dissolved in 150
mL of hot ethanol, and a solution prepared by dissolving 11.5 g
(47.9 mmol) of Na.sub.2S.9H.sub.2O in hot ethanol and water is
added thereto. The resulting mixture is agitated at 80.degree. C.
for 5 hours and cooled down to room temperature. Then, a
precipitated crystal is filtered, washed several times with water,
and dried, to give 4.3 g (13.2 mmol) of
4-amino-4'-octyloxyazobenzene. A yield of the compound is 82%.
[0159] The 4-amino-4'-octyloxyazobenzene is analyzed by .sup.1H
NMR.
[0160] The .sup.1H NMR analysis result is as follows.
[0161] 1H NMR (300 MHz, CDCl3) .delta. (ppm): 0.89 (t, J=6.9 Hz,
3H, CH3), 1.26-1.34 (m, 8H, CH2.times.4), 1.45-1.49 (m, 2H, CH2),
1.57-1.83 (m, 2H, CH2), 3.98 (br s, 2H, NH2), 4.02 (t, J=6.6 Hz,
2H, OCH2), 6.74 (d, J=8.9 Hz, 2H, ArH), 6.97 (d, J=8.9 Hz, 2H,
ArH), 7.76 (d, J=8.9 Hz, 2H, ArH), 7.82 (d, J=8.9 Hz, 2H, ArH).
1-2. Synthesis of Bisazo Compound
[0162] 2 g (6.15 mmol) of the 4-amino-4'-octyloxyazobenzene is
dissolved in 120 mL of dimethyl acetamide (DMAc) and 30 mL of
acetic acid (AcOH), and 3 mL of 12N HCl is added thereto. The
mixture is maintained at 0.degree. C. Then, 446 mg (6.46 mmol) of
sodium nitrate (NaNO.sub.2) is dissolved in 2 mL of water to
prepare a solution. The solution is slowly added by drops to the
reaction mixture. When the addition is complete, the reactant is
agitated for one hour while being maintained at 0.degree. C. Next,
a solution prepared by dissolving 6.15 mmol of 3-methylaniline
(m-toluidine) in 150 mL of methanol is slowly added by drops to the
mixture. The resulting mixture is agitated at 0.degree. C. for 1
hour. Then, the agitated mixture is neutralized with a sodium
hydroxide (NaOH) aqueous solution. When the reaction is complete, a
precipitated solid therein is filtered. The remaining mixture is
purified through silica gel column chromatography, to give a bisazo
compound. A yield of the compound is 60 to 80%.
1-3. Synthesis of Triazo Compound
[0163] 1 mmol of the bisazo compound is dissolved in 20 mL of
dimethyl acetamide (DMAc) and 5 mL of acetic acid (AcOH), and 5 mL
of 12N HCl is added thereto. The mixture is maintained at 0.degree.
C. Next, a solution prepared by dissolving 72 mg (1.04 mmol) of
sodium nitrate (NaNO.sub.2) in 1 mL of water and slowly added by
drops to the reaction mixture. When the addition is complete, the
reactant is agitated for one hour while being maintained 0.degree.
C. Next, a solution prepared by dissolving 206 mg (1 mmol) of
3-diethylaminophenylacetamide (N-(3-(diethylamino)phenyl)acetamide)
in 25 mL of methanol, and 2 mL of dimethyl acetamide (DMAc) is
slowly added by drops to the reaction mixture. The resulting
mixture is agitated at 0.degree. C. for one hour. The agitated
mixture is neutralized with a sodium hydroxide (NaOH) aqueous
solution. When the reaction is complete, a precipitated solid is
filtered. The remaining mixture is purified through silica gel
column chromatography (n-hexane:EtOAc=3:1), to give 449 mg (0.68
mmol) of a triazo dichroic dye represented by the following
Chemical Formula 3a. The yield is 68%.
##STR00008##
[0164] The dichroic dye represented by the above Chemical Formula
3a is analyzed by .sup.1H NMR.
[0165] The .sup.1H NMR analysis result is as follows.
[0166] .sup.1H NMR (300 MHz, CDCl3) .delta. (ppm): 0.90 (t, J=6.8
Hz, 3H, CH.sub.3), 1.22-1.36 (m, 14H, CH.sub.2.times.4,
CH.sub.3.times.2), 1.45-1.49 (m, 2H, CH.sub.2), 1.81-1.86 (m, 2H,
CH.sub.2), 2.29 (s, 3H, Ac), 2.85 (s, 3H, CH.sub.3), 3.49 (q,
J=14.0, 6.9, 4H, CH.sub.2.times.2), 4.06 (t, J=6.6 Hz, 2H,
OCH.sub.2), 6.50 (dd, J=9.3, 2.7 Hz, 1H, ArH), 7.02 (d, J=9.0 Hz,
2H, ArH), 7.66-8.14 (m, 11H, ArH).
Synthesis Example 2
[0167] 419 mg (0.62 mmol) of a dichroic dye represented by the
following Chemical Formula 4a is prepared according to the same
method as Synthesis Example 1, except for using 3-methoxy aniline
instead of 3-methylaniline in the process of synthesizing of a
bisazo compound. The yield is 62%.
##STR00009##
[0168] The dichroic dye represented by the above Chemical Formula
4a is analyzed by .sup.1H NMR.
[0169] The .sup.1H NMR analysis result is as follows.
[0170] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. (ppm): 0.90 (t,
J=6.7 Hz, 3H, CH.sub.3), 1.22-1.36 (m, 14H, CH.sub.2.times.4,
CH.sub.3.times.2), 1.45-1.51 (m, 2H, CH.sub.2), 1.80-1.86 (m, 2H,
CH.sub.2), 2.29 (s, 3H, Ac), 3.50 (q, J=14.1, 7.0, 4 H,
CH.sub.2.times.2), 4.06 (t, J=6.6 Hz, 2H, OCH.sub.2), 4.15 (s, 3H,
OCH.sub.3), 6.50 (dd, J=9.2, 2.7 Hz, 1H, ArH), 7.02 (d, J=9.0 Hz,
2H, ArH), 7.51-8.14 (m, 11H, ArH).
Synthesis Example 3
[0171] 425 mg (0.64 mmol) of a dichroic dye represented by the
following Chemical Formula 5a is prepared according to the same
method as Synthesis Example 1, except for using 3-fluoroaniline
instead of 3-methylaniline in the process of synthesizing of a
bisazo compound. The yield is 64%.
##STR00010##
[0172] The dichroic dye represented by the Chemical Formula 5a is
analyzed by .sup.1H NMR.
[0173] The .sup.1H NMR analysis result is as follows.
[0174] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. (ppm): 0.90 (t,
J=6.7 Hz, 3H, CH.sub.3), 1.22-1.36 (m, 14H, CH.sub.2.times.4,
CH.sub.3.times.2), 1.45-1.51 (m, 2H, CH.sub.2), 1.80-1.86 (m, 2H,
CH.sub.2), 2.30 (s, 3H, Ac), 3.51 (q, J=14.2, 7.1, 4 H,
CH.sub.2.times.2), 4.06 (t, J=6.6 Hz, 2H, OCH.sub.2), 6.50 (dd,
J=9.1, 2.7 Hz, 1H, ArH), 7.02 (d, J=9.0 Hz, 2H, ArH), 7.78-8.19 (m,
11H, ArH).
Synthesis Example 4
[0175] 449 mg (0.65 mmol) of a dichroic dye represented by the
following Chemical Formula 6a is prepared according to the same
method as Synthesis Example 1, except for using
3-diethylamino-4-methoxyphenylacetamide
(N-(3-(diethylamino)-4-methoxyphenyl)acetamide) instead of
3-diethylaminophenylacetamide. The yield is 65%.
##STR00011##
[0176] The dichroic dye represented by the Chemical Formula 6a is
analyzed by .sup.1H NMR.
[0177] The .sup.1H NMR analysis result is as follows.
[0178] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. (ppm): 0.90 (t,
J=6.7 Hz, 3H, CH.sub.3), 1.19-1.36 (m, 14H, CH.sub.2.times.4,
CH.sub.3.times.2), 1.45-1.51 (m, 2H, CH.sub.2), 1.80-1.86 (m, 2H,
CH.sub.2), 2.29 (s, 3H, Ac), 2.86 (s, 3H, CH.sub.3), 3.44 (q,
J=14.1, 7.1, 4 H, CH.sub.2.times.2), 3.91 (s, 3H, OCH.sub.3), 4.06
(t, J=6.5 Hz, 2H, OCH.sub.2), 7.02 (d, J=9.0 Hz, 2H, ArH), 7.37 (s,
1H, ArH), 7.77-8.25 (m, 10H, ArH).
[0179] Evaluation 1: Solubility Parameter
[0180] Solubility parameters of the dichroic dyes according to
Synthesis Examples 1 to 4 and Comparative Synthesis Example 1 are
calculated.
[0181] The solubility parameters are Hildebrand solubility
parameters.
[0182] Intermolecular cohesion is a combination of Van der Waals
and dipole moments inside molecules, and energy causing such
cohesion is referred to as cohesive energy ("Ecoh"). Such cohesive
energy may be changes of internal energy per 1 mole, and may be
represented by the following Relationship Equation 1.
E.sub.coh=.DELTA.U=.DELTA.H-.DELTA.T Relationship Equation 1
[0183] In Relationship Equation 1,
[0184] E.sub.coh is cohesive energy,
[0185] .DELTA.U is changes of internal energy per 1 mole,
[0186] .DELTA.H is enthalpy changes, and
[0187] .DELTA.T is temperature changes.
[0188] Cohesive energy per unit volume may be defined as cohesive
energy density ("CED"), which may be obtained by the following
Relationship Equation 2.
CED=(.DELTA.H-RT)/Vm Relationship Equation 2
[0189] In Relationship Equation 2,
[0190] CED is a cohesive energy density,
[0191] .DELTA.H is enthalpy changes, R is a gas constant,
[0192] T is a temperature, and
[0193] Vm is a mole volume.
[0194] The cohesive energy density is used to define the solubility
parameter that numerically indicates dissolution performance by
Hildebrand, and the solubility parameter may be calculated by the
following Relationship Equation 3 using a density or mole volume at
a predetermined temperature.
.delta.=(CED).sup.0.5=(.SIGMA.Ecoh.sub.i/.SIGMA.Vm.sub.i).sup.0.5
Relationship Equation 3
[0195] In Relationship Equation 3,
[0196] .delta. is a solubility parameter,
[0197] CED is a cohesive energy density,
[0198] Ecoh.sub.i is cohesive energy for a functional group i
inside a molecule, and
[0199] Vm.sub.i is a molar volume of the i functional group on the
molecule.
[0200] Hildebrand solubility parameter values used for designing a
structure of a dichroic dye may be calculated by group contribution
of molecules.
[0201] The group contribution of cohesive energy ("Ecoh") and mole
volume ("Vm") used for calculating a solubility parameter of a
dichroic dye is shown in Table 1, in accordance with Polym. Eng.
Sci. 1974, 14, 147; J. Appl. Polym. Sci. 2005, 96, 416, the content
of which is incorporated herein by reference in its entirety.
TABLE-US-00001 TABLE 1 Group Ecoh (J/mol) Vm (cm.sup.3/mol)
--CH.sub.3 4707 33.5 --CH.sub.2-- 4937 16.1 --CH-- 3431 -1.0 C 1464
-19.2 H.sub.2C.dbd. 4310 28.5 --CH.dbd. 4310 13.5 C.dbd. 4310 -5.5
Phenyl 31,924 71.4 Phenylene (o, m, p) 31,924 52.4 Phenyl
(trisubstituted) 31,924 33.4 Phenyl (tetrasubstituted) 31,924 14.4
Phenyl (pentasubstituted) 31,924 -4.6 Phenyl (hexasubstituted)
31,924 -23.6 Ring closure 5 or more atoms 1046 16.0 Ring closure 3
or 4 atoms 3138 18.0 --COOH 27,614 28.5 --CO.sub.2-- 17,991 18.0
--CO-- 17,364 10.8 --CONH-- 33,472 9.5 --NH.sub.2 12,552 19.2
--NH-- 8368 4.5 N 4184 -9.0 --N.dbd. 11,715 5.0 --N.dbd.N-- 4188
0.0 --CN 25,522 24.0 NO.sub.2 15,355 32.0 --O-- 3347 3.8 --OH
29,790 10.0 S 14,142 12.0 --F 4184 18.0 --Cl 11,548 24.0 --Br
15,481 30.0 --I 19,037 31.5
[0202] Solubility parameter of the dichroic dyes according to
Synthesis Example 1 to 4 which are calculated by a Hildebrand
solubility parameter are shown in Table 2.
TABLE-US-00002 TABLE 2 Solubility parameter Synthesis Example 1
22.6 Synthesis Example 2 22.7 Synthesis Example 3 22.9 Synthesis
Example 4 22.1
Manufacturing Polarization Film
Example 1
[0203] A composition for a polarization film is prepared by mixing
a polyolefin (solubility parameter: 16.6) including polypropylene
("PP") and a polypropylene-polyethylene ("PP-PE") copolymer in a
ratio of 5:5 (weight/weight), and 0.5 parts by weight of the
dichroic dye according to the Synthesis Example 1 based on 100
parts by weight of the polyolefin.
[0204] The composition for a polarization film is melt-kneaded at
about 250.degree. C. using a micro-compounder ("DSM"). The melt
blend is put in a sheet mold and pressed at a high temperature and
a high pressure, manufacturing a film. The film is elongated 1,000%
in a uniaxial direction (Instron Ltd.) at 125.degree. C.,
manufacturing a polarization film.
Example 2
[0205] A polarization film is manufactured according to the same
method as Example 1, except for using the dichroic dye according to
Synthesis Example 2 instead of the dichroic dye according to
Synthesis Example 1.
Example 3
[0206] A polarization film is manufactured according to the same
method as Example 1, except for using the dichroic dye according to
Synthesis Example 3 instead of the dichroic dye according to
Synthesis Example 1.
Example 4
[0207] A polarization film is manufactured according to the same
method as Example 1, except for using the dichroic dye according to
Synthesis Example 4 instead of the dichroic dye according to
Synthesis Example 1.
[0208] Evaluation 2: Polarization Characteristic
[0209] The polarization films according to Examples 1 to 4 are
evaluated regarding transmittance, polarization efficiency, and
dichroic ratio.
[0210] The transmittance is evaluated using a V-7100 UV/Vis
spectrophotometer (JASCO Inc.).
[0211] The transmittance is evaluated by respectively measuring
light transmittance of light entering parallel to the transmissive
axis of the polarization film and light transmittance of light
entering perpendicular to the transmissive axis of the polarization
film.
[0212] The transmittance is used to calculate a dichroic ratio
("DR") and polarization efficiency ("PE").
[0213] The dichroic ratio ("DR") is obtained according to the
following Equation 1.
DR=Log(1/T.sub..perp.)/Log(1/T.sub..parallel. Equation 1
[0214] In Equation 1,
[0215] DR denotes a dichroic ratio,
[0216] T.sub..parallel. is transmittance for light entering
parallel to the transmissive axis of a polarization film, and
[0217] T.sub..perp. is transmittance for light entering
perpendicular to the transmissive axis of the polarization
film.
[0218] The polarization efficiency is obtained according to the
following Equation 2.
PE(%)=[(T.sub..parallel.-T.sub..perp.)/(T.sub..parallel.+T.sub..perp.)].-
sup.1/2.times.100 Equation 2
[0219] In Equation 2,
[0220] PE denotes polarization efficiency,
[0221] T.sub..parallel. is transmittance for light entering
parallel to the transmissive axis of a polarization film, and
[0222] T.sub..perp. is transmittance for light entering
perpendicular to the transmissive axis of the polarization
film.
[0223] The results are illustrated referring to Table 3 and FIG.
4.
[0224] FIG. 4 is a graph showing dichroic ratios in a visible ray
region according to the polarization films according to Examples 1
to 4.
[0225] In Table 3, light transmittance, polarization efficiency,
and dichroic ratio of the polarization films according to Examples
1 to 4 are measured at the maximum absorption wavelength
(".lamda..sub.max").
TABLE-US-00003 TABLE 3 Polar- Solubility Transmit- ization Dichroic
parameter .lamda..sub.max tance efficiency ratio difference (nm)
(Ts, %) (PE, %) (DR) (dye-polyolefin) Example 525 34.74 99.60 4.6
6.0 1 Example 525 35.56 99.32 4.6 6.1 2 Example 530 37.10 98.88 4.5
6.3 3 Example 550 33.53 98.45 3.8 5.5 4
[0226] Referring to Table 3 and FIG. 4, the polarization films
according to Example 1 to 4 show polarization efficiency of greater
than or equal to 90% and dichroic ratios of greater than or equal
to 3.0 while satisfying light transmittance of greater than or
equal to 30%.
[0227] While this disclosure has been described in connection with
what is presently considered to be practical exemplary embodiments,
it is to be understood that the invention is not limited to the
disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the appended claims.
* * * * *